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Re: Ideas about beacons



At 05:50 AM 12/2/2005, Bruce Robertson wrote:
>When I decided to dip into satellite operations, I never imagined how much
>fun it would put back into *listening* to the radio. To paraphrase what
>Emily once wrote, there's something wonderous about hearing a satellite
>appear where it should, when it should. I'm also firmly convinced that
>decoding telemetry is a quid pro quod which we can offer groups which might
>be otherwise not be interested lifting amateur transponders.

Thanks for your kind words Bruce.  I still feel this way - it's quite 
a lot of fun.  I also get kick out of copying images from the NOAA 
weather satellites and hope to eventually have a GOES satellite downlink.

>On these topics I want to offer the following ideas for comment:
>
>1. A CW beacon is incredibly more useful than an always-on carrier.

I think CW beacons are useful, but the constant carrier has it's uses 
too.  I find it easier to track doppler because "it's always 
there".  One of the real fun things I did with UO-22's beacon was to 
use a spectrum analyzer to watch the carrier move across the passband 
as the doppler shift changed.  It gave me a chance to do some cool 
things like measure the relative gain and beam width of my antennas, 
etc.  I generally think beacons are useful in ways that are only 
limited by imagination.

I'd also like to give kudos to the SSETI team's carrier pulse beacon 
and the decoding software written by Seindil Loganadane.  I was very 
impressed with it's ease of use, how well it performed and the 
information it transmitted.  I was also looking forward to G6LVB's 
DTMFFFT beacon and was really sad that we didn't get a chance to try it out.

>2. William's point that the CW beacon should indicate mode is a very good
>one. AO-51's already great usefulness would be augmented if we could tune
>into a 435 MHz beacon and occasionally read 'MODE V/S' or 'MODE V USB / U'
>or what have you.

I would go farther and say that it could and should indicate the 
current schedule.  I was disappointed when AO-51 went operational 
that one of the panels in TLMEcho didn't contain this 
information.  Getting the schedule "from the bird" like AO-13 and 
AO-40 was far more exciting than having to go to the website.  No 
reason we shouldn't be able to get ephemeris this way as well.

>3. Projects which hope to collect data from amateurs should make it a
>design goal for any related software that it operate on as many OSes as
>possible....In fact, the server-side approach would mean that the XI-V team
>could peek at what people are decoding and even add a 'submit this data'
>button so the user could hand the data over with no effort.

This is a very good idea indeed, and a very thin client app connected 
to a server could do it in near real time.  A simple client to 
demodulate the TLM (or read a serial port where the TNC is connected) 
could stream the demodulated data to the server.  The server would 
decode it and send formatted TLM back to the client for display.  The 
server could determine the quality of TLM by looking at the bit error 
rate, and if it was decoded correctly it would automatically catalog 
it in real time for analysis by another process.

73,

Emily
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